Stabilized soap composition



STABILIZED SOAP COMPOSITION Richard C. Harshman, Kenmore, N.Y., andVictor C. Fnsco, Baltimore, Md., assignors to Olin Mathieson ChemicalCorporation, a corporation of Virginia No Drawing. Filed Apr. 14, 1955,Ser. No. 501,437

Claims. (Cl. 252-407) This invention relates to improved compositionscontaining fatty acid radicals. More particularly, it relates to soapcompositions stabilized with respect to color and odor formation by theincorporation therein of hydrazides. In a more particular aspect, thisinvention relates to the stabilization of soap compositions containingphenolic bactericides by the incorporation therein of hydrazides.

The tendency of soaps to discolor and become rancid in storage or use iswell known. These effects have been attributed to a variety of causesincluding the manufacture of soaps from fats and oils which themselvestend to become rancid. It is also believed that min-or metalliccontaminants particularly iron and copper in minute amounts acceleratethe formation of oxidation products resulting in undesirable odor ordiscoloration. These effects may appear in various forms of soapincluding bar soap, powdered soap, granulated soap and spray-dried soapsin the form of beads.

The principal method of attack of this problem has been to add variousanti-oxidants or other stabilizers to soap compositions in an effort toovercome these effects' Many of these suggested inhibitors afford apartial solution, for example, in inhibiting odor formation withoutaffecting or even deleteriously affecting color stability.

Soaps in liquid form, usually potassium soaps, are more difficult tostabilize in these respects than sodium soaps and many of the proposedstabilizers are generally unsatisfactory for the production of stablepotassium soaps or blends containing substantial amounts of potassiumsoaps.

The problem of soap stabilization has more recently been furtheraggravated by the incorporation of phenolic bactericides in soap.Although phenolic anti-oxidants have been proposed for the stabilizationof soap, many are ineffective and some phenolic compounds evenaccelerate the deterioration. A commonly used phenolic bactericide insoap is 2,2'-dihydroxy-3,5,,6,3,5,6'-hexachlorodiphenylmethane(hexachlorophene). Small proportions, for example, 0.5 percent in soapappear to acelerate color formation. This effect may be masked by theincorporation of yellow coloring matter in the composition so thatsubsequent yellowing during storage or use is not so obvious. Theproblem of incorporation of such phenolic bactericides in white toiletsoap so far has not been solved. It is important therefore to providenew and improved stabilizers for soap which are effective in thepresence of phenolic bactericides.

It has now been discovered that soap compositions can be stabilized bythe incorporation therein of minor proportions of hydrazides. It hasfurther been discovered that these stabilizers are particularlyeffective in soap compositions containing phenolic bactericides.

Useful prosit) 2,953,438 Patented Dec. 6, 1960 portions of thehydrazides vary from a minimum effective amount. suitably about 0.05percent to about 1 percent by weight, based on the weight of the soap.

Suitable hydrazides which can be used in accordance with the presentinvention include the monohydrazides of aliphatic monocarboxylic acidscontaining from 1 to 18 carbon atoms, such as formic acid hydrazide,acetic acid hydrazide, propionic acid hydrazide, butyric acid hydrazide,valeric acid hydrazide, caproic acid hydrazide, lauric acid hydrazide,myristic acid hydrazide, palmitic acid hydrazide, stearic acid hydrazideand elaidic acid hydrazide. The hydrazides of dibasic acids, such asthose derived from oxalic acid, malonic acid, succinic acid, glutaricacid, adipic acid, pimelic acid, azelaic acid, sebaeic acid and fumaricacid can also be utilized. Also useful are the hydrazides of monobasicaromatic acids, such as benzoic acid hydrazide, o-nitrobenzoic acidhydrazide, p-nitrobenzoic acid hydrazide, o-toluic acid hydrazide,p-toluic acid hydrazide, m-toluic acid hydrazide, salicylic acidhydrazide, l-naphthoic acid hydrazide and 2-naphthoic acid hydrazide.The dihydrazide of carbonic acid, carbohydrazide, is also veryeffective. Hydrazides derived from substituted hydrazines can be used,for example, the betahydroxyethylhydrazide of stearic acid, thedi-(betahydroxyethyl) hydrazide of stearic acid, the unsymmetricaldimethylhydrazide of oleic acid and the phenylhydrazide of kerylbenzenesulfonic acid. Mixtures of hydrazides of organic acids, hydrazides ofmixed fatty acids and mixtures of hydrazides with known compatible soapstabilizers can be used.

The stabilizers should not be added to the soap compositions at a stagewhich will result in decomposition, leaching, or deterioration of thestabilizing agent. They can be incorporated in the soap compositions atany convenient step after the saponification. For example, they can beadded to the neat soap as made in the kettle in the manufacture of framesoap. In the manufacture of milled soap, it is ordinarily preferable toadd the stabilizer to the mixer preceding the milling together withperfume materials and coloring agents if desired. The stabilizer canalso be incorporated during the crutching process. The stabilizers canbe added conveniently in the form of aqueous solutions where thestabilizers are water soluble or they can be incorporated as dry solids,preferably finely divided. Mixing subsequent to the addition of thestabilizer should be sufficient to render the soap compositionhomogeneous.

The soap product can subsequently be dried and formed into cakes,plates, beads or other forms as desired. In the manufacture of liquidsoap compositions the stabilizers can be dissolved in the soap solutionsor aqueous solutions of the stabilizers when conveniently prepared canbe added to the liquid soap composition.

The stabilizers are effective in soaps subsequently incorporated incosmetic compositions including tooth paste, face creams and bodycreams.

Example I Blends of soap with acetic hydrazide and sebacic dihydrazidewere prepared by thoroughly mixing 0.5 part by weight of the hydrazidewith 99.5 parts by weight of dried pure soap stock (essentially thesodium salt of tallow fatty acids) at room temperature. The mixture waspressed into 20 gram bars under a pressure of 2000 p.s.i.g. Four testbars of each hydrazide blend and four similar bars prepared from thesame soap stock omitting the hydrazide were stored in an oven at C;

Light Re- Stabilizer, percent Treatment fiectance,

percent None... Unheated. 1000 Do. Heated.-- 65. 5 Acetic hydrazide, 0.5weight percent do 64. 3 Sebacle dihydrazide, 0.5 weight percent -do 75.1

The data show extensive color development in the untreated soap causedby the accelerated test. Significant inhibition of color development isshown by the addition of either acetic hydrazide or sebacic dihydrazide.

Example II Acetic hydrazide and carbohydrazide were tested asstabilizers by the test described in Example I. The following resultswere obtained:

T iht Refiectance, percent Stabilizer, percent Treatment Nrme T nheated100.

Do.-' Heated 30. 5 A eti hydrazlde, 0.05 wel-ht percent -do 43. 5Garbohydrazide, 0.5 weight percent .d 49.

Even at a concentration of 0.05 weight percent, acetic hydrazide showedsignificant improvement in preventing color formation. Carbohydrazide at0.5 weight percent was also very effective.

Example III White soap flakes (essentially the sodium soap of tallowfatty acids) were used as the soap stock in further Laurie hydrazide ata concentration of 0.05 weight percent showed a significantstabilization of the soap with respect to color development.

Example IV A liquid potassium coconut oil soap was prepared by heating amixture of 420 grams of coconut oil, 300 grams of 36 percent aqueouspotassium hydroxide and 1867 grams of water on a steam bath for 16hours. Suificient2,2'-dihydroxy-3,5,6,3,5',6'-hexachlorodiphenylmethane, also known ashexachlorophene, was dissolved in the solution so that it contained 0.5weight percent of the hexachlorophrene, based on the dry weight of thesoap. To a 50 milliliter portion of the soap solution containinghexachlorophene was added 0.26 gram of stean'c hydrazide. The sameamount of myristic hydrazide was added to another 50 milliliter portionof the soap solution. The two test samples together with a 50 millilitertest sample containing hexachlorophene and another withouthexachlorophene were heated in an oven at 100-420 C. for two weeks. Mostof the water evaporated from the samples after a few hours of heating.At the end of the heating period, the samples were cooled to 28 C. anddiluted to 50 milliliters with water. Any insoluble matter was removedby filtration and the light transmission of the filtrate was determinedusing a No. 525 series blue filter in a Fischer electrophotometer. Theresults shown in the followlng table were obtained: 1

Hexachloro- Light Stabilizer phene,per- Treatment Transmiscent sion,percent None Unheated. 100.0

None Heated 60.0

Myristic hydrazide 0.5 do 54.0

The data show that the hexachlorophene adversely affects the colorstability of the soap solution and that the two hydrazides materiallyimprove the stability in this respect.

Example V Additional quantities of the same potassium soap solution asused in the preceding example were used in the following tests. Severalhydrazides and commercial stabilizers were dissolved in separate 50milliliter portions of the soap solution already containing 0.5 weightpercent of hexacchlorophene, based on dry soap weight, to make solutionscontaining 0.5 weight percent of the stabilizer, also based on dry soapweight. A portion of each solution was sealed in a glass amp-ule andheated in an oven at C. for two weeks. At the end of this time, theampules were cooled, opened and the percent light transmission based onthat of the original unheated solution as percent was measured with aFischer electrophotometer using a No. 525 Series blue filter. Theresults shown in the following table were obtained:

The test is less severe than that of Example IV since the unstabi-iizedsoap after the test had a light transmission of 87.5 percent of theoriginal. The hydrazides tested, however, showed material stabilizationagainst the development of color. This is in contrast to the twocommercial stabilizers which even appear to have an accelerating effect.

Various modifications can be made in the procedures of the specificexamples to provide other improved soap and soap-containing compositionsfalling within the scope of our invention. Our invention is generallyapplicable for the purpose of improving the properties of soaps andsoap-containing compositions as those terms are generally understood inthe art. In the specific examples, the soaps employed were sodium soapsof tallow fatty acids or a potassium soap of coconut oil fatty acids.Other soaps can be substituted for those specifically used, and ourinvention comprehends the improvement of soaps and compositionscontaining them in which the cationic portion is, for example, ammonia,an amine, an alkali metal or an alkaline earth metal, such as sodium,potassium, lithium, calcium, barium, and so forth, as well as magnesium,aluminum, zinc and cadmium. The anionic portion of the soap is generallyderived from one or more aliphatic nonocarboxylic acids containing from12 to 18 carbon atoms, such as lauric acid, myristic acid, palmiticacid, stearic acid, oleic acid, and so forth. The soaps suitable for usein our invention can also be derived in known manner from a wide varietyof naturally-occurring materials or derivatives thereof, includ' ingtallow, palm oil, hydrogenated marine oils such as whale oil, coconutoil, palm kernel oil, rosin, tall oil.

lard, olive oil, cottonseed oil, peanut oil, soya bean oil, linseed oil,and so forth. Also, various other phenolic bactericides can besubstituted for the hexachlorophenes used in the examples, among thembeing hexylresorcinol, cresol, thymol, chlorothymol and guaiacol.

Hydrazides may also be incorporated in greases. These are commonlysoap-thickened petroleum oils containing lithium, sodium, calcium,aluminum or other metal soaps of various acids including those derivedfrom tall oil, tallow, castor oil or waste fat acids, for example.

We claim:

1. A soap composition consisting essentially of an alkali metal soap ofan aliphatic monocarboxylic acid containing from 12 to 18 carbon atomsand as a stabilizer a hydrazide selected from the group consisting ofacetic acid hydrazide, sebacic acid dihydrazide, carbohydrazide, lauricacid hydrazide, myristic acid hydrazide and stearic acid hydrazide inamount from 0.05 to 1 percent by weight, based upon the weight of thesoap.

2. A composition according to claim 1 in which the soap is a sodiumsoap.

3. A composition according to claim 1 in which the soap is a potassiumsoap.

4. A composition according to claim 1 also containing an amount of aphenolic bactericide suificient to impart bactericidal action to thesoap.

5. A composition according to claim 1 in which the hydrazide is aceticacid hydrazide.

6. A composition according to claim 1 in which the hydrazide is sebacicacid dihydrazide.

7. A composition according to claim 1 in which the hydrazide iscarbohydrazide.

8. A composition according to claim 1 in which the hydrazide is lauricacid hydrazide.

9. A composition according to claim 1 in which the hydrazide is stearicacid hydrazide.

10. A composition according to claim 1 in which the soap is a sodiumsoap and in which the hydrazide is acetic acid hydrazide.

11. A composition according to claim 1 in which the soap is a sodiumsoap and in which the hydrazide is sebacic acid dihydrazide.

12. A composition according to claim 1 in which the soap is a sodiumsoap and in which the hydrazide is carbohydrazide.

13. A composition according to claim 1 in which the soap is a sodiumsoap and in which the hydrazicle is lauric acid hydrazide.

14. A composition according to claim 1 in which the soap is a sodiumsoap and in which the hydrazide is stearic acid hydrazide.

15. A composition according to claim 1 also containing an amount of 2,2dihydroxy 3,5,6,3',5',6 hexachlorodiphenylmethane sufficient to impartbactericidal action to the soap.

References Cited in the file of this patent UNITED STATES PATENTS1,973,724 Perkins et al Sept. 18, 1934 2,014,924 Benedict Sept. 17, 19352,535,077 Kunz et al. Dec. 26, 1950 2,680,122 Black et al. June 1, 19542,729,690 Oldenburg Jan. 3, 1956 2,730,502 Beaver et al. Ian. 10, 19562,808,416 Bell et al. Oct. 1, 1957 FOREIGN PATENTS 423,938 Great BritainFeb. 11, 1935 OTHER REFERENCES Ind. and Eng. Chem, July 1926, pp. 691-4,article by Smith.

Chemical Abstracts, vol. 26 (1932), page 5864.

1. A SOAP COMPOSITION CONSISTING ESSENTIALLY OF AN ALKALI METAL SOAP OFAN ALIPHATIC MONOCARBOXYLIC ACID CONTAINING FROM 12 TO 18 CARBON ATOMSAND AS A STABILIZER A HYDRAZIDE SELECTED FROM THE GROUP CONSISTING OFACETIC ACID HYDRAZIDE SEBACIC ACID DIHYDRAZIDE, CARBOHYDRAZIDE, LAURICACID HYDRAZIDE, MYRISTIC ACID HYDRAZIDE AND STEARIC ACID HYDRAZIDE INAMOUNT FROM 0.05 TO 1 PERCENT BY WEIGHT, BASED UPON THE WEIGHT OF THESOAP
 15. A COMPOSITION ACCORDING TO CLAIM 1 ALSO CONTAINING AN AMOUNT OF2,2''-DIHYDROXY-3,5,6,3'',5'',6''-HEXACHLORODIPHENYLMETHANE SUFFICIENTTO IMPART BACTERICIDAL ACTION TO THE SOAP.